Smoking Intention and Progression From E-Cigarette Use to Cigarette Smoking

OBJECTIVES: To investigate whether the prospective association between electronic cigarette (e-cigarette) use and cigarette smoking is dependent on smoking intention status. METHODS: Waves 2 and 3 data of the Population Assessment of Tobacco and Health (PATH) Study, a US nationally representative prospective cohort study of tobacco use. Data were collected in 2014-2015 (wave 2) and 2015-2016 (wave 3) and analyzed in 2019. RESULTS: At wave 2, 12.8% of adolescent never-smokers of conventional cigarettes had intention to smoke and 8.5% had ever used an e-cigarette. At wave 3, 3.2% had ever smoked a cigarette. Both smoking intention and ever using e-cigarettes at wave 2 were positively associated with cigarette smoking at wave 3 (adjusted odds ratio [aOR] = 3.03; 95% confidence interval [CI] = 1.97-4.68, P < .001; aOR = 4.62, 95% CI = 2.87-7.42, P < .001, respectively). The interaction between smoking intention and ever using e-cigarettes was significant (aOR = 0.34, 95% CI = 0.18-0.64, P < .01). Among adolescents who had expressed intention to smoke conventional cigarettes at wave 2, the odds of cigarette smoking at wave 3 did not significantly differ for e-cigarette users and never e-cigarette users (aOR = 1.57; 95% CI 0.94-2.63; P = .08). Among adolescents who had no intention to smoke at wave 2, e-cigarette users, compared with never e-cigarette users, had >4 times the odds of cigarette smoking (aOR = 4.62; 95% CI 2.87-7.42; P < .0001). CONCLUSIONS: E-cigarette use is associated with increased odds of cigarette smoking among adolescents who had no previous smoking intention. E-cigarette use may create intention to smoke and/or nicotine use disorder that lead to onset of cigarette smoking.